Effect of Methane, CO2, and H2S on the Solubility of Methyl and Ethyl Mercaptans in a 25 wt % Methyldiethanolamine Aqueous Solution at 333 and 365 K

We have investigated the solubility of methanethiol and ethanethiol (methyl and ethyl mercaptans in an aqueous methyldiethanolamine solution (25 wt %)) by using a static analytic method at 333 and 365 K. The measurements were done for different pressures of methane in the absence of acid gas with individual acid gas present and with a mixture of acid gases present (CO2 and/or H2S). Additional measurements of Henry's law constants were realized by considering the gas stripping method. The effect of total pressure (realized by the addition of methane) and the effect of acid gas loading for a constant total pressure around 7 MPa were studied. The increasing pressure and acid gas loading increase the apparent Henry's law constant of the mercaptan, highlighting a drop out effect of the mercaptans.

Automated summary

The solubility of methanethiol and ethanethiol in an aqueous methyldiethanolamine solution was investigated using a static analytic method. The study found that increasing pressure and acid gas loading can increase the apparent Henry's law constant of the mercaptans.